Final answer:
Cancer arises from genetic mutations that result in the activation of oncogenes and/or the inactivation of tumor suppressor genes, disrupting cell cycle regulation and leading to uncontrolled cell proliferation.
Step-by-step explanation:
In relation to causes of cancer, genetic mutations are active oncogenes and/or inactive tumor suppressor genes.
Oncogenes and Tumor Suppressor Genes in Cancer
Cancer can occur due to mutations in genes that regulate the cell cycle. Two critical types of regulatory genes are proto-oncogenes and tumor-suppressor genes. Proto-oncogenes, when mutated or overexpressed, can become oncogenes that encourage cell proliferation. Tumor suppressor genes, on the other hand, function as the cell's brake to prevent unregulated cell growth. The most well-studied example is the p53 gene, acting as a transcription factor to halt proliferation upon DNA damage.
Both sets of genes must be significantly altered for cancer to develop. A series of mutations that activate oncogenes and inactivate tumor suppressor genes must transpire, disrupting the balance between cell growth and regulation. This loss of regulation leads to the uncontrolled cell division characteristic of cancer cells.